Fed ended 2014 with $4.5T in assets driven by QE3

The U.S. Federal Reserve ended last year with $4.49 trillion in assets, up $473 billion from the previous year as a result of its third round of quantitative easing. The central bank ended the bond buying program last fall.

The Fed's operating expenses fell to $6 billion from $6.1 billion in 2013, according to revised audited financials from the central bank.